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POS Glass Tip Range of Liquid Level Switches

The POS Glass Tip range of liquid level switches are robust and rugged, ideal for operation in harsh industrial environments, aggressive chemicals and extreme temperatures up to 140°C.

The POS Glass Tip sensor is solid state, combining an infra-red LED and phototransistor which are optically coupled by the tip when the sensor is in air. When the sensing tip is immersed in liquid, the infra-red light escapes making the output change state. The sensor can detect the presence or absence of almost any liquid type, oil or water based.

Options of N and P type outputs can sink or source up to 200mA at a supply voltage range from 12 to 28Vdc and can be configured to be a high or low signal in either a wet or dry state. The sensor is available with a M12 connector or 3 core cable and also has LED output indication.

The stainless steel body combined with a crystal glass sensing tip allows the POS Glass Tip range of liquid level switches to operate under high pressure conditions up to 80 bar and across two temperature ranges; Standard (-40 to 100°C) or Extended (-40 to 140ºC).


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Part Numbering Guide


Supply Voltage (Vs) 12 to 28Vdc
Supply Current (Is) 25mA max
Output Sink and Source Current (Iout) 200mA max
Operating Temperatures Standard: -25°C to +100°C
or Extended: -40°C to +140°C
Storage Temperatures Standard: -25°C to +100°C
or Extended: -40°C to +140°C
Housing Material Stainless steel with simax crystal glass tip
Sensor Terminations M12 Brad Harrison connector
or PUR 3×0.25mm², 2m cable
Operating Pressure 0 to 80 bar




Output Voltage (Vout): Iout = 200mA
Vs = 12 to 28Vdc
Output High Vout = Vs – 1.5V max
Output Low Vout = 0V + 0.5V max


Wire Designation
Brown Vs
Black Output*
Blue 0V

*See part numbering guide for output type and logic

**See datasheet for information on Brad Harrison connector


  • Designed for applications requiring a robust metal housing and a wide operating temperature range
  • Reverse polarity, ESD, transient over-voltage and short circuit protected
  • Wide supply voltage ranges
  • N and P type output configurations, capable of sinking or sourcing up to 200mA, can directly drive small loads
  • Standard and extended temperature ranges available
  • Stainless steel housing with simex glass sensing tip
  • Choice of terminations
  • Very high operating pressure
  • LED output indication


  • Solid state so no moving parts to cause unreliability
  • Fast response time
  • Repeatable switching point
  • Very robust construction permitting use in a wide range of demanding applications
  • Compatible with most fluids and chemicals
  • SST Sensing’s highest operating temperature liquid level switch


Liquid sensing 001_450

When in air the infrared light is reflected back to the detector


Liquid sensing 002_450

When in liquid the infrared light is refracted and the output switches

  • This field is for validation purposes and should be left unchanged.